Can I use Blender to create an open loop race car track level?
As J.Doe yes you definitely can! There's even tutorials on that exact task, 

https://www.youtube.com/watch?v=SDLLbKvEeBY

Although this specific video is on a loop track making an open one wouldn't be much different I don't think. Of course depending on what you're actually trying to do you may need to look for more specific tutorials, like if you're making it for animation inside blender or if it's intended for a game or perhaps you want terrain around your track, there's tutorials out there for a lot of tasks in blender if you need them. Best of luck! :)